TRS-ARM — Comms

TRS-ARM uses the same hardware interfaces as TRS-GND and TRS-ECU.

Interface Usage in TRS-ARM

Interface	Role in TRS-ARM
RFM95W (915 MHz LoRa)	Arming radio link to TRS-GND
FC Switch (NMOS1/NMOS2)	Active — arms/disarms Easy Mini flight computer
GC-XPORT-ENH (Ethernet)	Not connected in flight
USB-C	Pre-flight debug/flash only

Radio Link

[TRS-ARM - Rocket AV Bay]
           ^
           │
  [RFM95W 915 MHz LoRa]
           │  
  [TRS-GND - Test Stand] <── Ethernet ──> [Network Switch - Bunker] <── Ethernet ──> [Router - Test Stand]
                                                                                               ^
                                                                                               │
                                                                                            Ethernet
                                                                                               │
                                                                                               v
                                                                                     [GSE Laptop / GUI PC]

TRS-ARM communicates only via radio during flight. There is no wired Ethernet connection once the rocket is integrated.

FC Switch Protocol

The FC switch is controlled by the STM32 in response to arm/disarm commands received over the LoRa link from the ground.

Command (from ground)	STM32 Action	FC Switch State
ARM	Assert LOGICA1 / LOGICB1	Closed — Easy Mini powered
DISARM	De-assert LOGICA1 / LOGICB1	Open — Easy Mini unpowered